EFFECTS OF ANTI-RHEUMATIC COMPOUNDS AND PYRIDINE DERIVATIVES ON THE CUTANEOUS RESPONSE TO THURFYL NICOTINATE IN THE GUINEA-PIG.

The effects of certain anti-rheumatic drugs and compounds related to nicotinic acid on the cutaneous response to locally applied thurfyl nicotinate in guinea-pigs were investigated. Sodium salicylate, aspirin or phenylbutazone administered orally each reduced the response to thurfyl nicotinate at about half the dose needed for equivalent protection against the cutaneous effects of exposure to ultra-violet light. Nicotinic acid or thurfyl nicotinate given orally flushed the skin and reduced the intensity of the local reaction to thurfyl nicotinate without affecting the response to ultra-violet light. Nicotinamide, isonicotinic acid, picolinic acid and quinolinic acid were less effective in producing flushes and in reducing the effect of locally applied thurfyl nicotinate. The flush induced in guinea-pigs by oral nicotinic acid was reduced by the previous administration of phenylbutazone. Possible mechanisms for these effects are discussed.